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Web Security ApplianceApplication · Cisco

CVE-2019-1672

MEDIUM · 5.8 CVSS v3.0 Published 2019-02-08
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
67/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability in the Decryption Policy Default Action functionality of the Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to bypass a configured drop policy and allow traffic onto the network that should have been denied. The vulnerability is due to the incorrect handling of SSL-encrypted traffic when Decrypt for End-User Notification is disabled in the configuration. An attacker could exploit this vulnerability by sending a SSL connection through the affected device. A successful exploit could allow the attacker to bypass a configured drop policy to block specific SSL connections. Releases 10.1.x and 10.5.x are affected.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The Cisco Web Security Appliance has a vulnerability in its Decryption Policy Default Action feature. When Decrypt for End-User Notification is disabled, the appliance incorrectly handles SSL-encrypted traffic, allowing an unauthenticated remote attacker to bypass a configured drop policy. This enables SSL connections that should be blocked to pass through the WSA, effectively bypassing intended security controls.

MitigationEnsure the Decryption Policy Default Action is properly configured and consider upgrading to a patched release (Cisco WSA releases later than 10.1.x and 10.5.x). Alternatively, enable Decrypt for End-User Notification if business requirements permit, as this addresses the incorrect handling of SSL traffic.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Web Security ApplianceApplication
Affected:= 10.1.0-204= 10.5.2-072= 11.5.1-fcs-115

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Cisco WSA version
    Access the WSA admin interface (GUI) and navigate to System Administration > System Status, or run CLI command 'version' to obtain the installed firmware version.
    Affected if The installed version matches 10.1.0-204, 10.5.2-072, or 11.5.1-fcs-115 exactly.
  2. Verify Decryption Policy exists
    Navigate to Web Security Manager > Decryption Policies in the WSA GUI, or use CLI command ' decryptionpolicies ' to confirm at least one decryption policy is configured.
    Affected if A Decryption Policy with a default action (Drop, Allow, or Monitor) is defined.
  3. Check Decrypt for End-User Notification setting
    In WSA GUI, go to Web Security Manager > Decryption Policies, select the active policy, and locate the 'Decrypt for End-User Notification' option. Verify whether it is enabled or disabled.
    Affected if Decrypt for End-User Notification is DISABLED while a default action is set to Drop.
  4. Confirm SSL traffic bypass condition
    Review the Decryption Policy Default Action: if set to 'Drop' and Decrypt for End-User Notification is disabled on the affected version, SSL connections that should be blocked are passing through.
    Affected if Default Action is configured to Drop and Decrypt for End-User Notification is disabled, enabling traffic that should be blocked to traverse the WSA.

A user is affected if running exactly version 10.1.0-204, 10.5.2-072, or 11.5.1-fcs-115 with a Decryption Policy Default Action set to Drop while Decrypt for End-User Notification is disabled.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Ensure the Decryption Policy Default Action is properly configured and consider upgrading to a patched release (Cisco WSA releases later than 10.1.x and 10.5.x). Alternatively, enable Decrypt for End-User Notification if business requirements permit, as this addresses the incorrect handling of SSL traffic.

Fix this in Web Security Appliance Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing8.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,800
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2019-1672 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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